var page = 1;

function loadXMLDoc() {
	var xmlhttp;
	if (window.XMLHttpRequest) {
		//  IE7+, Firefox, Chrome, Opera, Safari 浏览器执行代码
		xmlhttp = new XMLHttpRequest();
	} else {
		// IE6, IE5 浏览器执行代码
		xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
	}
	xmlhttp.onreadystatechange = function() {
		if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
			var json = JSON.parse(xmlhttp.responseText);
			//对数组进行循环
			for (let i = 0; i < json.shop.length; i++) {
				console.log(json.shop[i]);
				//创建html结构
				var img = document.createElement("img");
				img.src = json.shop[i].pic;
				var h3 = document.createElement("h3");
				h3.innerHTML = json.shop[i].title;
				var p = document.createElement("p");
				p.innerHTML = json.shop[i].desc;
				var p2 = document.createElement("p");
				p2.innerHTML = "￥";
				var span = document.createElement("span");
				span.innerHTML = json.shop[i].price;
				var del = document.createElement("span");
				del.innerHTML = json.shop[i].pricedel;
				span.appendChild(del);
				p2.appendChild(span);
				var div = document.createElement("div");
				div.appendChild(img);
				div.appendChild(h3);
				div.appendChild(p);
				div.appendChild(p2);
				//把所有的div追加到#list里面
				document.querySelector("#list").appendChild(div)
			}
		}
	}
	xmlhttp.open("GET", page+".json", true);
	xmlhttp.send();
}
loadXMLDoc()

document.querySelector("#btn").addEventListener('click', function() {
	if (page >= 4) {
		page = 1;
	} else {
		page++;
	}
	//先清空
	document.querySelector("#list").innerHTML = "";
	//再取数据放到#list里面
	loadXMLDoc();
})
